Space-Borne Remote Sensing of Soil Moisture and Freeze/Thaw Dynamics at High Resolution Using a Combined Active and Passive Instrument Concept
Abstract
The design and expected characteristics of a space-borne system for high-resolution mapping of surface soil moisture and soil freeze/thaw dynamics is presented. This study represents the proposal for a comprehensive terrestrial hydrology monitoring mission. The mission objective is traced to the data requirements of research related to predictability, variations and change in the rate of the hydrologic cycle. The baseline mission builds on the heritage of ground-based and airborne passive and active low frequency microwave measurements that have demonstrated and validated the effectiveness of the measurements and associated algorithms for estimating the amount and phase of surface soil moisture. The satellite has both a radiometer and a radar on board. The radiometer provides polarized brightness temperature fields at 1.4 GHz across a wide swath (~ 900 km) at a resolution of 40 km. The radar operates at 1.2 GHz (VV, HH, and HV) and is capable of high-resolution mapping (less than 3 km) over 70 percent of the swath and low-resolution across the remainder. All terrestrial land regions are revisited within 2-3 days. The instrument uses a light-weight deployable mesh reflector antenna to make conical scans at a constant-incidence angle. The antenna scans at 6 rpm to generate the wide swath and mapping coverage. The algorithm design for producing 40 km and 10 km soil moisture and freeze/thaw data products and 3 km freeze/thaw and inundation extent products will be described. The strategy for estimating and correcting for wet biomass masking of the soil moisture and freeze/thaw signal by vegetation (with cover less than forest cover) will be presented. Finally we present a strategy for using data assimilation to use the synergy of measurements from other platforms, in situ data, and physical constraints on water and energy transports and balances to develop value-added data products that are continuous in time and provide estimates of soil water availability in the root-zone that is beyond the sensing depth of remote sensing systems.
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2001
- Bibcode:
- 2001AGUSM...H61A04E
- Keywords:
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- 1640 Remote sensing;
- 1833 Hydroclimatology;
- 1863 Snow and ice (1827);
- 1866 Soil moisture;
- 1894 Instruments and techniques